Thermostatically controlled key lock heater



Dec. 18, 1956. R. R. SEMMONS THERMOSTATICALLY CONTROLLED KEY LOCK HEATER Filed Oct. 21, 1954 3 4 F2 p z :1 i 1 r 1 wul w 7 W 3 5 2 \3 W 9 in 7 A 23 3 2 2 7 w in J 1 fa Z a 0 M a 4 9 WWW/WA W 2 WNW m 2T K 1/ 7 4 a z 5 U M W INVENTOR Z zb/emozza R JIz'znmozzs BY yfl/ygvr ATTORNEY V United States Patent THERMOSTATICALLY CONTROLLED KEY LOCK HEATER Richmond R. Simmons, Columbus, Ohio Application October 21, 1954, Serial No. 463,681

3 Claims. (Cl. 219-19) This invention is directed to an improved electrically energized heating means for key locks, and its general object is to provide a simple, effective and compact heating means capable of being readily accommodated within the confines of a lock casing and which is operative upon the insertion of an actuating key in the lock mechanism to close an energizing circuit in which is embodied a heatliberating resistor coil arranged in adjoining relation to the lock mechanism.

Another object of the invention is to provide a lockheating means in which the coil-energizing circuit includes a normally open switch, the latter having an actuating element so arranged within the lock that, when the operating key for the lock is inserted therein, one end of the key will engage the switch-actuating element to move the latter to a position of circuit closure, thereby energizing the heating coil and applying heat to the lock mechanism to melt ice, or other congealed fluids or accumulations present in the mechanism and which are of an operation-obstructing order, interfering with the movement of the operating parts of the lock.

A further object is to provide lock-heating mechanism of this character wherein the normally-open resistor coil circuit, in addition to the key-actuated switch for closing the same, is provided with an automatic thermostatic switch, the latter being so adjusted as to cause the circuit to remain open independently of the key-actuated switch until a predetermined lock temperature obtains in the lock and which is capable of freezing moisture or admitting of the presence of ice within the lock.

For a further understanding of the invention, including additional objects or advantages thereof, reference is to be had to the following description and the accompanying drawing, wherein:

Fig. 1 is a vertical longitudinal sectional view disclosing the improved electrically heated key-actuated lock mechanism of the present invention;

Fig. 2' is a vertical transverse sectional view taken through the mechanism on the plane indicated substantially by the line 22 of Fig. 1;

Fig. 3 is a similar view on the line 33 of Fig. 1.

In general, the present invention provides a heater for key-actuated motor vehicle door locks. Such locks in cold and freezing weather accumulate moisture deposits and liquid films which freeze and solidify in a manner often making it impossible to operate the locks in a customary manner. By incorporating an electrical heating means in such locks, and rendering the same operative by the insertion of a lock-operating key, such obstructing deposits may be readily melted and the normal functioning of the lock regained.

Accordingly, the present invention provides a coiled electrical resistance element, mounted in a suitable dielectric holder, which is disposed in surrounding relation to the movable tumbler parts of an automobile door lock. Connected in series circuit with the electrically energized heat-liberating coil is a first normally open spring pressed switch. This switch is so disposed within the lock assem- Patented Dec. 18, 1956 bly that it may be moved to its position of circuit closure in response to the full insertion of the removable operating key within the lock. In addition to the first switch, the mechanism includes a normally open second switch arranged in series with the first switch and the heating coil of the circuit, the second switch being thermostatically controlled, whereby the coil-operating circuit may be closed or established when temperatures ambient to the lock are of the order of 32 F. or lower. Under these conditions when the lock key is inserted, the first switch is moved by the manual operation involved to its position of circuit completion, and with the second switch thermostatically closed the full coil circuit is thereby completed and the coil energized to heat the lock, such heating being continued until the lock key is removed from engagement with the first switch, which results in the opening of the operating circuit.

The specific construction illustrated in the accompanying drawings for carrying out the invention comprises a tubular outer housing or casing 1 which has its flanged outer end 2 received in an opening 3 formed in a door panel 4. The flanged outer end of the housing provides an annular seating shoulder 5 which bears on the outer surface of the panel 4 around the opening 3 therein. lmmediately to the rear of the shoulder 5 the outer wall of the housing or casing is exteriorly threaded at 6 to receive a clamping nut 7 by which the casing 1 and the mechanism contained therein may be oper-ative'ly mounted in a stationary manner in connection with a vehicle door, or the like. The opposite or inner end of the casing 1 is closed by a removable end plate 8.

integrally formed with the flanged outer end 2 of the casing and extending inwardly therefrom in coaxial order is a stationary sleeve 9. The outer cylindrical surfaces of this sleeve are spaced inwardly and concentrically from the inner surfaces of the outer wall of the casing to receive therebetween a ceramic or other dielectric collar 10. Embedded in this collar is a resistor or heater coil 11.

Within the sleeve 9 there is mounted the barrel 12 of a standard key-actuated tumbler-type lock mechanism, the outer ends of lock tumblers 13 being receivable in a longitudinal groove 14 provided in the inner face of the sleeve 9 in precluding normal rotation of the barrel 12 and its associated crank arm or latching extension 15, the latter projecting through an arcuate slot 16 formed in the casing 1 for engagement with an associated stationary frame-mounted keeper plate, not shown. By the insertion of a conventional key, such as that indicated at 17, into the key-receiving slot 18 of the barrel 12, the tumblers 13 will be engaged by the serrated edge of the key and withdrawn from the groove 14, thus admitting of the rotation of the barrel and its associated latching extension by manually effected turning forces applied to the barrel through the enlarged outer gripping end of the key.

Positioned in the casing 1, in longitudinally spaced relation from the inner end of the sleeve 9, is a manually operated or first switch 19 for closing the operating circuit 20 in which the coil 11 is arranged. In this instance, the switch 20 is shown as comprising a stationary mounting disk 21 of insulating material which is formed peripherally with a pair of spaced resilient contacts 22 and 22. These contacts are normal-1y spaced from but are adapted, upon key insertion in the lock, to be engaged by a pair of movable contacts 23 mounted on the ends of an arm 24 carried by a movable head 25. This head is fixed on the end of sliding shaft 26 having polygonal surfaces. Such surfaces engage those of an opening 27 formed axially in a closure plug 28, the latter being threaded in one end of the sleeve 9. Centrally thereof the plug 28 is formed with a tubular boss 29 which is received in one end of the lock barrel 12. Within the bore of the boss 29 the shaft 26 projects and is provided with an enlarged end 30 3 which is adapted to be engaged by the shank end of the key 17 when the latter is fully inserted into the lock. The end of the key pressing on the end 30 of the shaft 26 slides the latter outwardly against the resistance of a spring 31 confined in the boss 29, causing the contacts 23 on the arm 24 to engage the resilient contacts 22 of the disk 21 and to thus, in part, complete the circuit 20 through the key-actuated or first switch 19.

In order that the heater will be operated only when there exists a need for the same, I employ a second or thermostatic switch 32 which is placed in series with the switch 19 in the coil circuit 20. As shown, the switch involves a gas-filled bellows 33 which, when cooled to a temperature of 32 F. or lower, contracts sutficiently to cause the contacts 34 carried on the ends of an arm 35. which is mounted on the stem element 36 of the bellows, to engage stationary contact terminals 37 and 37 mounted on an insulating disk 38, the latter being stationarily ar ranged within the interior of the casing 1. The terminal 37 is joined with one of the conductors 39 comprising the circuit 2% and leads to a source of electrical energy D, such as the storage battery of a motor vehicle electrical system. The terminal 37 is joined by a conductor it) to the terminal contact 22' of the first switch 19. The contact 22 of the first switch is joined by a conductor with one end of the resistor coil 11, the opposite end of said coil being grounded on the casing 1 and the casing, in turn, is provided with a ground 42 leading to the ground 43 of the battery E.

The stem element 36 of the bellows 33 is formed, in this instance, with a socket for the fixed reception of the polygonal shank of a headed pin 43. Movably positioned on this shank is the non-rotatable arm 35 and a spring surrounds the pin shank and is confined between the headed outer end of the pin and the central portion of the arm 35. The arm 35 moves normally in unison with the bellows stem 36, but when the contacts 34 of the arm are in seated engagement with the terminals 37 and 37, any continued contraction of the bellows is absorbed by the spring 44 without injury to the mechanism of the thermostatic switch.

In view of the foregoing, it will be seen that the present invention provides a simple yet etfective means for releasing frozen door locks employed in any capacity, where exposure to the elements is present. It will be noted that current is used in heating the lock only when the two switches 19 and 32 are closed in completing the heater circuit. Even under conditions of freezing ten"- peratures, unless the lock is frozen, little or no current is used or wasted, since if the lock is not frozen, with the thermostatic switch closed because of low-temperature conditions, the relatively short period of time the key remains in the lock in unlocking the same does not produce any appreciable battery drain. If the lock is frozen, however, the key is retained in the lock in circuit-completing contact with the switch 19 until the lock is heated internally to temperatures, and for a period of time, sufficient to effect melting of the obstructing frozen material present in the lock confines. The construction is characterized by its compactness, simplicity and its positively acting economical design. This design is such as to enable the entire heated lock assembly to be conveniently mounted in the door construction, for instance, of a motor vehicle with the conductor 39 leading through the hinge axis of the door. By forming the heater as a component part of the lock assembly, the key is heated while it is operatively positioned in the lock, it being required that the key 17 be fully inserted in the lock in order to close the first switch of the operating circuit and that tempera tures of the atmosphere in which the lock is disposed be at freezing or lower before the second switch can be closed and the heating coil energized. It will be understood that my improved electrically heated lock may be used in any capacity to which it may be found applicable.

I claim:

1. Switch-controlled electrically energized heating means for key-operated locks, comprising: a housing formed with an internal chamber in which the keyreceiving barrel of such a lock is positioned; a resistor coil positioned in said housing in heat-exchanging relation with said lock barrel; a normally open switch mounted in said housing and connected in series circuit with said coil and having a movable actuating element arranged to close said swtch in response to the insertion of a key within said barrel; and a temperature-responsive switch electrically connected in series with said first-named switch and said coil and being arranged to close upon a predetermined low temperature.

2. Switch-controlling electrical heating means for key locks, comprising: a stationary supporting housing formed with a coaxial internal sleeve; a lock barrel rotatably positioned within said sleeve, key-actuated tumbler means carried by said barrel and engageable with said sleeve to govern rotation of the barrel; a resistor coil; insulating means supporting said coil within the housing in heattransmitting relation to said barrel; a normally open switch mounted in said housing; a movable actuating element for said switch disposed in longitudinal alignment with said barrel for engagement with a key inserted in said barrel to cause said switch to assume a position of circuit closure; and a temperature-responsive switch electrically connected in series circuit with said first-named switch and said resistor coil and arranged to be closed in response to a predetermined low ambient temperature.

3. in combination with a key-actuated lock; an electrically-actuated heating means disposed in close thermal proximity to said lock and energizable to heat said lock; a first normally open switch electrically connected in series with said heating means and having an actuator for closing said switch in response to the full insertion of a key within said lock; and a second, normally open, thermostatic switch electrically connected in series with said heating means and said first switch and arranged to establish an operating circuit for said heating means in response to a given low ambient temperature.

References Cited in the file of this patent UNlTED STATES PATENTS 2,232,577 West Feb. 18, 1941 2,371,534 McGrath Mar. 13, 1945 2,530,513 Drugan Nov. 21, 1950 2,538,872 Jones Jan. 23, 1951 

